Ewan Wilson, a New Zealand-based air accident investigator and the founder of Kiwi Airlines, believes captain Zaharie Shah was mentally ill and that his actions ultimately resulted in the deaths of all those on board.

Furthermore Wilson, a veteran commercial pilot himself, alleges five previous incidents of “murder/suicide” in the aviation industry over the past three decades.

Wilson, whose book Good Night Malaysian 370: The Truth Behind The Loss Of Flight 370, was released in July, is in Birmingham to meet with aviation experts to discuss his findings and “have a candid chat about mental health screening for pilots in the airline industry.”

The authors say the most likely scenario is that Shah deliberately depressurised the cabin, thereby depriving those on board of oxygen and causing them to lose consciousness for up to four hours before the Boeing 777 disappeared beneath the waves.

Although oxygen masks would have dropped down automatically from above the seats, the available supply was limited to just 20 minutes.

Those unable to grab a mask, including sleeping passengers, would have passed out within the space of a few minutes.

The entire 'ghost plane', including her cabin crew whose air supply is only marginally longer, would have slipped into a coma and died shortly after from hypoxia.

Shah, who locked his co-pilot out of the cockpit, survived long enough - either by re-pressurising the aircraft, or from breathing his own, more extensive air supply - to evade radar and "execute his master plan", the pair conclude.

They say he then performed a controlled ditching in the sea, which would explain why no debris has been found because the plane landed and sank in one piece.

Feng Zhishang cries as family members mark the birthday of his son Feng Dong, a passenger onboard the Malaysia Airlines flight MH370